In a typical TDMA communication system, most telecommunication services have substantially the same channel structure, i.e., a single time slot on a single carrier. Thus, channel allocation is relatively straightforward.
However, the introduction of more powerful and complex services requires the allocation of different numbers of time slots and carriers for different users. The particular combinations of time slots and carriers can be referred to as "channel structures". The allocation of different types of channel structures in a communication system is significantly more complicated than the case where the channel structures of all users are identical. Appropriate channel allocation methods are desirable to efficiently allocate resources without blocking.
U.S. Pat. No. 5,542,093 discloses a method for redistributing dual mode mobile units to extended channel groups to reduce congestion in primary channel groups. If there is a shortage of channels for single mode mobiles, the system allocates a new call to a channel type which is in lesser demand if the new call is for a multi-mode mobile, or the system hands off multi-mode mobile stations from a first group of channels to a second group of channels or vice versa to create free channels.
However, the prior art does not describe efficient methods for allocating resources to communication system users which request services requiring different numbers of slots and carriers within the same group of channels.
In a typical wireless communication, some number of frequencies are allocated to an operator to be divided over the operator's coverage area. These frequencies could be further divided into timeslots or spread spectrum codes or both. In the case where the frequencies are further divided into timeslots, the channels can be said to form a "resource area". It can be difficult to allocate users to these channel resources efficiently if different users require different channel structures; i.e., different combinations of adjacent channel portions (e.g., frequencies and/or timeslots).
For example, in a case where six services with different channel structures are to use the same resource area which includes frequencies f.sub.0 -f.sub.5 and the time slots ts0-ts7, simple random allocation can result in a situation as shown in FIG. 1. There are many empty areas (which designate potentially available resources) but very few where more of the defined structures could be accommodated. It is quite clear that this is not a spectrum efficient strategy.
Therefore, it would be desirable to efficiently allocate channel resources from a resource area for different users requiring different channel structures.